Stock-Based Compensation Plans (Narrative) (Details) (USD $)	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Maximum Value To Be Purchased During Calendar Year			$ 25,000
Maximum Number Of Shares To Be Purchased During Purchase Period			10,000
Percentage Of Maximum Employee Contribution	10.00%		10.00%
Percentage Of Minimum Employee Contribution	1.00%		1.00%
Percentage Of Share Of Non Vested Stock Considered As Call Option	85.00%		85.00%
Stock Authorized Shares Employee Stock Purchase Plans			1,500,000
Shares available for grant	6,700,000		6,700,000
Compensation cost related to restricted shares	1,800,000	2,000,000	3,700,000	4,900,000
Share Based Payment Award Value	4,200,000		4,200,000		5,200,000
Compensation expense	1,200,000	1,600,000	3,600,000	4,600,000
Liability long-term incentive compensation plan	8,000,000		8,000,000		9,900,000
Liability long-term incentive compensation plan variable portion	$ 7,300,000		$ 7,300,000		$ 8,500,000
Share-based Compensation Arrangement by Share-based Payment Award, Number of Additional Shares Authorized			4,300,000
Maximum Shares As Incentive Options Member
Deferred Compensation Arrangement with Individual, Share-based Payments [Line Items]
Shares available for grant	2,000,000		2,000,000